TWI463456B - Source driver and display device - Google Patents

Description

Source driver and display device

The present invention relates to a source driver and display device, and more particularly to a source driver and display device that can utilize a gamma voltage corresponding to a different gamma curve to generate a pixel voltage.

Modern life is full of various types of display devices, so users can view the desired image, whether in the home, in the office, in the conference room, or even in the vehicle. In contrast, the display device must be able to provide an image of the appropriate grayscale performance in accordance with local conditions. In addition, the brightness perceived by the human eye is not linear with respect to changes in ambient light intensity. Therefore, in order to improve the user's gray scale deviation caused by the brightness of the environment, it is usually adjusted or compensated by the gamma curve.

In order to further improve the quality of images, in today's display devices, techniques for correcting image frames using a plurality of gamma curves have been developed. In general, existing display devices achieve gamma curve switching by defining additional control signals in the timing controller. However, this practice must change the original design architecture of the timing controller, thereby increasing the design difficulty of the timing controller and the manufacturing cost of the display device.

The invention provides a source driver capable of outputting pixel voltages corresponding to different gamma curves according to a picture start signal and a start pulse signal.

The invention provides a display device, wherein a source driver can output pixel voltages corresponding to different gamma curves according to a picture start signal and a start pulse signal from a timing controller to drive the display panel.

The invention provides a source driver comprising a gamma curve selection unit and a drive channel. The gamma curve selection unit selects a plurality of gamma curves as a specific gamma curve according to the picture start signal and the start pulse signal, and generates a control signal according to the specific gamma curve. The driving channel reads the picture data according to the start signal of the picture, converts the picture data into a pixel voltage according to a specific gamma curve, and outputs the pixel voltage according to the start pulse signal.

In an embodiment of the invention, the gamma curve selection unit includes a counter and a controller. The counter resets the count value according to the start signal of the screen, and accumulates the count value according to the start pulse signal. The controller queries the gamma curve table according to the count value to select one of the plurality of gamma curves as a specific gamma curve, and generates a corresponding control signal with reference to the specific gamma curve.

In an embodiment of the invention, the gamma curve selection unit comprises a counter. The counter resets the count value according to the start signal of the screen, and accumulates the count value according to the start pulse signal. The gamma curve selection unit outputs a count value as a control signal.

In an embodiment of the invention, the drive channel includes a plurality of digital analog converters and a multiplexer. The plurality of digital analog converters are in one-to-one correspondence with the plurality of gamma curves. Wherein, each digital analog converter receives a plurality of gamma voltages according to the corresponding gamma curve, and converts the picture data into gray scale voltages according to the plurality of gamma voltages. The multiplexer is electrically connected to the digital analog converter, and selects a digital analog converter corresponding to a specific gamma curve according to the control signal, and outputs a gray scale voltage from the selected digital analog converter as a pixel voltage.

The invention provides a display device comprising a display panel, a timing controller and a source driver. The timing controller outputs the picture start signal and the start pulse signal. The source driver is electrically connected to the timing controller and includes a gamma curve selection unit and a drive channel. The gamma curve selection unit selects a plurality of gamma curves as a specific gamma curve according to the picture start signal and the start pulse signal, and generates a control signal according to the specific gamma curve. The driving channel reads the picture data according to the start signal of the picture, converts the picture data into a pixel voltage according to a specific gamma curve, and outputs the pixel voltage according to the start pulse signal.

Based on the above, the present invention uses the picture start signal from the timing controller and the start pulse signal to generate control signals corresponding to different gamma curves, and uses the control signals to generate corresponding pixel voltages. In this way, the present invention can realize the switching control of the gamma curve without changing the architecture of the timing controller, thereby helping to reduce the design difficulty and the manufacturing cost of the display device.

The above described features and advantages of the present invention will be more apparent from the following description.

In the source driver and the display device proposed by the embodiments of the present invention, the switching control of the gamma curve can be achieved without changing the design of the timing controller, thereby improving the picture quality and reducing the manufacturing cost. In order to make the content of the present invention easier to understand, the following specific embodiments are illustrative of the embodiments of the present invention. In addition, wherever possible, the elements and/

1 is a schematic diagram of a display device in accordance with an embodiment of the present invention. Referring to FIG. 1 , the display device 100 includes a timing controller 110 , gate drivers 120_1 - 120_m , source drivers 130_1 - 130_n , and a display panel 140 . The gate drivers 120_1~120_m and the source drivers 130_1~130_n are electrically connected to the timing controller 110 and the display panel 140.

In practical applications, the control signals generated by the timing controller 110 include a picture start signal STV and a start pulse signal TP. The picture start signal STV is the start signal of each picture picture. Therefore, after the gate driver 120_1 receives the screen start signal STV, the gate drivers 120_1~120_m will sequentially output the scan signals to the scan lines in the display panel 140 to thereby drive the pixels in the display panel 140 ( Pixel). In other words, the gate drivers 120_1~120_m will drive the display panel 140 in accordance with the picture start signal STV. On the other hand, the source drivers 130_1~130_n will output the pixel voltages V_P1~V_Pn to the data lines in the display panel 140 with reference to the start pulse signal TP, thereby causing the display panel 140 to generate corresponding image frames.

In this embodiment, the source drivers 130_1~130_n perform latching and outputting of the picture data according to the start pulse signal TP. In addition, the source drivers 130_1~130_n further receive the picture start signal STV, and determine the driving order of the scan lines by the picture start signal STV and the start pulse signal TP. For example, FIG. 3 is a timing diagram of signals generated by a timing controller according to an embodiment of the invention. The picture start signal STV is the start signal of each display picture, and the start pulse signal TP includes a plurality of start pulses, for example, PU31~PU34.

As shown in FIG. 3, the source drivers 130_1~130_n provide corresponding pixel voltages for pixels connected to different scan lines one by one according to the start pulses PU31~PU34. In other words, the start pulses PU31~PU34 each correspond to a different scan line. Furthermore, the gate driver 120_1 drives the respective scan lines one by one from the first scan line according to the picture start signal STV. Therefore, if the start relationship of the start pulse PU31~PU34 and the scan line is defined one by one starting from the picture start signal STV, the first start pulse PU31 corresponds to the first scan line and the second start pulse PU32. The second scan line...etc, and so on. In other words, the source drivers 130_1~130_n can determine the driving order of the scan lines by the picture start signal STV and the start pulse signal TP.

Further, the source drivers 130_1~130_n generate the pixel voltages V_P1 to V_Pn using the gamma voltages corresponding to different gamma curves in accordance with the driving order of the scanning lines. Therefore, in this embodiment, the source drivers 130_1~130_n first select one of the plurality of gamma curves as the specific gamma curve according to the picture start signal STV and the start pulse signal TP. Thereafter, the source drivers 130_1~130_n convert the picture data into corresponding pixel voltages V_P1~V_Pn according to a specific gamma curve. Accordingly, the display device 100 of the present embodiment does not need to use an additional signal to control the switching of the gamma curve, but directly uses the picture start signal STV from the timing controller 110, as well as the general display device. The start pulse signal TP controls the switching of the gamma curve.

In order to further illustrate the present embodiment, FIG. 2 is a schematic diagram of a source driver in accordance with an embodiment of the present invention. Referring to FIG. 2, the source driver 130_1 includes a gamma curve selection unit 210 and a drive channel 220. The gamma curve selection unit 210 receives the picture start signal STV and the start pulse signal TP, and selects a plurality of gamma curves as a specific gamma curve according to the picture start signal STV and the start pulse signal TP. In addition, the gamma curve selection unit 210 generates the control signal S_G according to a specific gamma curve. On the other hand, the driving channel 220 receives the plurality of sets of gamma voltages V_G11~V_G1j, V_G21~V_G2j, . . . , V_Gi1~V_Gij corresponding to different gamma curves, for example, the gamma voltages V_G11~V_G1j correspond to the first gamma curve. The gamma voltage V_G21~V_G2j corresponds to the second gamma curve...etc. In addition, the driving channel 220 further converts the picture data into a pixel voltage V_P1 by referring to the gamma voltage corresponding to the specific gamma curve according to the control signal S_G.

In order to make the disclosure more complete, the internal structure of the gamma curve selection unit 210 and the drive channel 220 will be further described below. 4 is a circuit diagram of a source driver in accordance with an embodiment of the present invention. Referring to FIG. 4, the gamma curve selection unit 210 includes a counter 410 and a controller 420. The drive channel 220 includes a digital analog converter 431, a digital analog converter 432, a multiplexer 440, and an output buffer 450. The controller 420 is electrically connected to the counter 410. The input end of the multiplexer 440 is electrically connected to the digital analog converter 431 and the digital analog converter 432, and the output of the multiplexer 440 is electrically connected to the output buffer 450.

In actual operation, the counter 410 receives the picture start signal STV and the start pulse signal TP. In addition, the counter 410 resets the count value C according to the screen start signal STV, and accumulates the count value C according to the start pulse signal TP. For example, please refer to FIG. 3 and FIG. 4 simultaneously. When receiving the picture start signal STV, the counter 410 resets the count value C to zero. Next, the counter 410 will accumulate the count value C in accordance with the received start pulses PU31~PU34. For example, when the start pulse PU31 is received, the counter 410 accumulates the count value C once to cause the count value C to be equal to one. When the start pulse PU32 is received, the counter 410 accumulates the count value C again to cause the count value C to be equal to 2, and so on. Wherein, when the count value C is 1, the first scanning line in the display panel 140 is driven. When the count value C is 2, it means that the second scanning line in the display panel 140 is driven, and so on.

In other words, the controller 420 can determine the currently driven scan line according to the magnitude of the count value C. Therefore, in actual operation, the controller 420 will query the gamma curve table according to the count value C. For example, if the two gamma curves GA and GB are switched as an example, Table 1 lists the correspondence between the scan line and the gamma curve. As shown in Table 1, in the present embodiment, for a pixel connected to an odd number of scanning lines (for example, SL1 and SL3), the source driver 130_1 uses a gamma voltage corresponding to the first gamma curve GA. A corresponding pixel voltage V_P1 is generated. For a pixel connected to an even number of scan lines (eg, SL2 and SL4), the source driver 130_1 generates a corresponding pixel voltage V_P1 using a gamma voltage corresponding to the second gamma curve GB.

Specifically, when the count value C is 1, the first scanning line SL1 in the display panel is driven. At this time, the controller 420 will select the first gamma curve GA as a specific gamma curve according to the count value C, and accordingly generate a corresponding control signal S_G, for example, logic 1. When the count value C is 2, the second scanning line SL2 in the display panel is driven. At this time, the controller 420 will select the second gamma curve GB as a specific gamma curve according to the count value C, and accordingly generate a corresponding control signal S_G, for example: logic 0. By analogy, when the count value C is 3, the controller 420 will generate a control signal _SG having a logic 1. When the count value C is 4, the controller 420 will generate a control signal S_G having a logic 0.

However, the correspondence shown in Table 1 is only one embodiment of the present invention. In other applications, the correspondence between the scan line and the gamma curve may also be such that the gamma curve is switched once for each of the two scan lines, for example, the first to the second, the fifth to the fifth, and the other of the scan lines correspond to the first gamma. The Ma curve, the 3~4, 7~8... scan lines correspond to the second gamma curve, and so on. Or, each of the three scan lines corresponds to a different three gamma curves, for example, the first, fourth, and seventh scan lines correspond to the first gamma curve, and the second, fifth, and eighth. The scan line corresponds to the second gamma curve, and the scan lines 3, 6, and 9 correspond to the third gamma curve, and so on, and the invention is not limited thereto.

Referring to FIG. 4 and Table 1, the digital analog converter 431 receives a plurality of gamma voltages V_G11~V_G1j corresponding to the first gamma curve GA, and converts the picture data D_img according to the gamma voltage gamma voltages V_G11~V_G1j. Gray scale voltage V_C1. The digital analog converter 432 receives a plurality of gamma voltages corresponding to the second gamma curve GB, and converts the picture material D_img into a grayscale voltage V_C2 according to the gamma voltages V_G21 to V_G2j.

The multiplexer 440 selects a digital analog converter corresponding to a specific gamma curve according to the control signal S_G, and outputs a gray scale voltage from the selected digital analog converter as the pixel voltage V_P. For example, when the control signal S_G is logic 1, that is, when the specific gamma curve is the first gamma curve GA, the multiplexer 440 will select and output the gray scale voltage V_C1 as the pixel voltage V_P1. When the control signal S_G is logic 0, that is, when the specific gamma curve is the second gamma curve GB, the multiplexer 440 will select and output the gray scale voltage V_C2 as the pixel voltage V_P1.

In other words, when the digital analog converters 431 and 432 receive the picture data D_img, the digital analog converters 431 and 432 respectively according to the gamma voltages V_G11 to V_G1j corresponding to the first gamma curve GA and the second gamma curve GB, respectively. With V_G21~V_G2j, the picture data D_img is converted into gray scale voltages V_C1, V_C2, and input to the multiplexer 440. Next, the multiplexer 440 further selects the gray scale voltage V_C1 or V_C2 according to the control signal S_G as the pixel voltage V_P1. Further, the output buffer 450 is for amplifying the pixel voltage V_P1 and outputting the amplified pixel voltage V_P1 to drive the display panel.

It should be noted that the detailed structure of the gamma curve selecting unit 210 enumerated in the embodiment of FIG. 4 is only an embodiment, but it is not intended to limit the present invention. For example, in the embodiment of FIG. 4, the gamma curve selecting unit 210 generates a control signal S_G whose logical level is 1 and 0 interleaved according to the picture start signal STV and the start pulse signal TP. In order to generate the control signal S_G of the above type, in other embodiments, those skilled in the art can selectively remove the controller 230 in the gamma curve selection unit 210 according to the design requirements, and directly use the count value C. As a control signal S_G.

For example, when the resolution of the count value C generated by the counter 410 is one bit, the magnitude of the count value C will switch between the logic 1 and the logic 0 with the accumulation of the start pulse. In other words, the change in the logic level of the count value C at this time will be equal to the change in the logic level of the control signal S_G in the embodiment of FIG. Therefore, the gamma curve selection unit 210 can directly output the count value C and regard it as the control signal S_G transmitted to the drive channel 220. In other words, the gamma curve selection unit 210 may also include only the counter 410, and may generate the control signal S_G corresponding to the specific gamma curve according to the picture start signal STV and the start pulse signal TP.

In summary, the source driver of the embodiment of the present invention uses the picture start signal and the start pulse signal from the timing controller to generate control signals corresponding to different gamma curves, and uses the control signals to generate corresponding pictures. Prime voltage. Thereby, the present invention can realize the switching control of the gamma curve without changing the architecture of the timing controller, thereby contributing to the design difficulty and the manufacturing cost of the display device.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

100. . . Display device

110. . . Timing controller

120_1~120_m. . . Gate driver

130_1~130_n. . . Source driver

140. . . Display panel

STV. . . Screen start signal

TP. . . Starting pulse signal

V_P1~V_Pn. . . Pixel voltage

210. . . Gamma curve selection unit

220. . . Drive channel

V_G11~V_G1j, V_G21~V_G2j,..., V_Gi1~V_Gij. . . Gamma voltage

PU31~PU34. . . Starting pulse

410. . . counter

420. . . Controller

431, 432. . . Digital analog converter

440. . . Multiplexer

450. . . Output buffer

C. . . Count value

D_img. . . Picture data

S_G. . . Control signal

V_C1, V_C2. . . Gray scale voltage

1 is a schematic diagram of a display device in accordance with an embodiment of the present invention.

2 is a schematic diagram of a source driver in accordance with an embodiment of the present invention.

3 is a timing diagram of signals generated by a timing controller according to an embodiment of the invention.

4 is a circuit diagram of a source driver in accordance with an embodiment of the present invention.

130_1. . . Source driver

210. . . Gamma curve selection unit

220. . . Drive channel

STV. . . Screen start signal

TP. . . Starting pulse signal

S_G. . . Control signal

V_P1. . . Pixel voltage

V_G11~V_G1j, V_G21~V_G2j,..., V_Gi1~V_Gij. . . Gamma voltage

Claims (12)

A source driver includes: a gamma curve selection unit that selects a plurality of gamma curves as a specific gamma curve according to a picture start signal and a start pulse signal, and generates according to the specific gamma curve a control signal; and a driving channel, according to the control signal, referencing the specific gamma curve to convert a picture data into a pixel voltage, and output the pixel voltage according to the starting pulse signal. The source driver of claim 1, wherein the picture start signal and the start pulse signal are from a timing controller. The source driver of claim 1, wherein the gamma curve selecting unit comprises: a counter, resetting a count value according to the start signal of the screen, and accumulating the meter according to the start pulse signal And a controller, querying a gamma curve table according to the count value, selecting one of the gamma curves as the specific gamma curve, and generating the corresponding control signal by referring to the specific gamma curve. The source driver of claim 1, wherein the gamma curve selecting unit comprises: a counter, resetting a count value according to the start signal of the screen, and accumulating the meter according to the start pulse signal And a value, wherein the gamma curve selecting unit outputs the count value as the control signal. The source driver of claim 1, wherein the driving channel comprises: a plurality of digital analog converters, one-to-one correspondence with the gamma curves, wherein each of the digital analog converters corresponds to The gamma curve receives a plurality of gamma voltages, and converts the picture data into a gray scale voltage according to the gamma voltages; and a multiplexer electrically connected to the digital analog converters and according to the control signals The digital analog converter corresponding to the specific gamma curve is selected, and the gray scale voltage from the selected digital analog converter is output as the pixel voltage. The source driver of claim 5, wherein the driving channel further comprises: an output buffer electrically connected to the multiplexer, and amplifying the pixel voltage, and outputting the enlarged image accordingly Prime voltage. A display device includes: a display panel; a timing controller that outputs a picture start signal and a start pulse signal; and a source driver electrically connected to the timing controller, including: a gamma curve selection unit, Selecting a plurality of gamma curves as a specific gamma curve according to the start signal of the picture and the start pulse signal, and generating a control signal according to the specific gamma curve; and a driving channel according to the control signal The picture data is converted into a pixel voltage by referring to the specific gamma curve, and the pixel voltage is output according to the start pulse signal. The display device of claim 7, further comprising: a gate driver electrically connected to the timing controller and the display panel, and driving the display panel according to the start signal of the screen. The display device of claim 7, wherein the gamma curve selection unit comprises: a counter, resetting a count value according to the start signal of the screen, and accumulating the count value according to the start pulse signal And a controller, querying a gamma curve table according to the count value, selecting one of the gamma curves as the specific gamma curve, and generating the corresponding control signal by referring to the specific gamma curve. The display device of claim 7, wherein the gamma curve selection unit comprises: a counter, resetting a count value according to the start signal of the screen, and accumulating the count value according to the start pulse signal The gamma curve selection unit outputs the count value as the control signal. The display device of claim 7, wherein the driving channel comprises: a plurality of digital analog converters, one-to-one correspondence with the gamma curves, wherein each of the digital analog converters is corresponding to The gamma curve receives a plurality of gamma voltages, and converts the picture data into a gray scale voltage according to the gamma voltages; and a multiplexer electrically connected to the digital analog converters and selects according to the control signals The digital analog converter corresponding to the particular gamma curve and outputting the gray scale voltage from the selected digital analog converter as the pixel voltage. The display device of claim 11, wherein the driving channel further comprises: an output buffer electrically connected to the multiplexer, and amplifying the pixel voltage, and outputting the amplified pixel according to the pixel Voltage.